Semiconductor metrology may be performed by explicitly measuring dimensions of semiconductor structures in electron-microscope images. For example, to measure line spacing (i.e., pitch), line edges as shown in a critical-dimension scanning-electron-microscope (CD-SEM) image are averaged and the distances between successive average values are determined. Such measurements may be noisy and inaccurate, however, and are hard to perform for arbitrary or complex structures. Non-geometric parameters (e.g., lithographic focus and dose) are difficult to determine using such measurements, as are some geometric parameters (e.g., overlay, film thickness, and sidewall angle). Such measurements also fail to exploit information in the images outside of the features being measured.